You shoud google for duolingo grammar notes. You'll find some for every course I imagine. The same people who originally created those courses made unofficial wikia or other pages and populate unofficial discords.
I'm using it for serious study in multiple languages. It's still plenty useful.
They are just not hosting the community interactions anymore. Probably because it was too difficult to keep it clean from abuse and they decided to be about educational technology rather than about hosting and curating social content.
I don’t understand. Why aren’t the notes in the app? I can already search for language information on the web. But I’d prefer it was just in the language learning app I’m using already.
Duolingo is driven by analytics. My guess is that they saw that almost nobody is using the notes compared to the app and it's too much work to maintain them. Also they have to keep them working for three platforms, which isn't all that trivial.
You just have to know to look for them...